A The degeneration of the intervertebral disk, in particular of the nucleus pulposus, results in a loss of height in the affected disk space which is associated with a weakening of the annulus fibrosus and of the ligaments. The spinal column hereby becomes instable at this position. The consequence is a horizontal displaceability of the vertebral bodies with respect to one another which results in impairments of the nerve roots in this region and/or of the spinal marrow with pain resulting therefrom.
The principle for the treatment of these symptoms consists of the surgical removal of the nucleus pulposus and the insertion of support bodies in order to restore the normal height of the disk space.
There are a variety of demands on both the surgeon performing an intervertebral disk procedure and on the spinal implants themselves.
A Transforaminal Lumbar Interbody Fusion (TLIF) is a posterior and lateral approach to the disc space. To gain access to the disc space, typically the facet joint is removed and access is gained via the nerve foramen. While more technically demanding of the surgeon than other fusion techniques, a TLIF offers a number of clinical advantages.
When compared to a PosteroLateral Fusion (PLF), a TLIF approach leaves much more of the soft tissue intact, which is less traumatic for the patient. Further, a PLF does not provide access to the disc space.
While a PosteroLateral InterBody Fusion (PLIF) provides access to the disc space, a TLIF approach also provides access to the interbody space, but without the need for manipulation of neural elements, reducing the risk of post-operative neural deficit. Additionally, in a TLIF, only a single implant is placed. More specifically the TLIF implant is placed in the anterior aspect of the disc space, thus providing space for a substantial fusion mass in the posterior aspect of the disc space where the natural compression occurs.
However, traditional TLIF procedures do suffer from shortcomings. For example, to place the desired implant in the anterior aspect of the disc space from an oblique posterior approach, traditional procedures demand that the implant be released from the inserter and then tamped into place. The two step insertion of this implant is generally recognized among surgeons as cumbersome.